1. Field of the Invention
The present invention relates to an improvement in the reverse gear system used in a motorcycle.
2. Discussion of Background
It is difficult to push a large motorcycle backward, i.e., to move a large motorcycle backward by human power. For this reason, a reverse gear system as shown in FIG. 6 and FIG. 7 has been provided as an optional part for a motorcycle.
In these figures, reference numeral 100 designates a main-shaft-side gear, which is coupled to the main-shaft in the gearbox of a motorcycle not shown. Reference numeral 101 designates a countershaft-side gear, which is coupled to the countershaft in the gearbox of the motorcycle. Reference numeral 102 designates an idler gear. Reference numeral 103 designates a shifter. Reference numeral 104 designates a ball, which is put, under the resilient force of a spring 105, into recesses 103a formed at upper and lower positions of the shifter 103 so that the ball selectively and provisionally holds the shifter 103 in a retracted position and in a forward position. When the motorcycle is driven backward, the reverse gear system is put in an ON position by pushing the shifter into the forward position from the retracted position with the gearbox being shifted to neutral to disengage the clutch. When the shifter has been pushed into the forward position, the idler gear is engaged with the main-shaft-side gear 100 as shown in FIG. 7. Accordingly, when the clutch is engaged, the countershaft-side gear is reversely rotated to make the rear wheel of the motorcycle rotated in the direction to drive the motorcycle backward.
In order to avoid inadvertent damage in, e.g., a case where the gearbox is shifted, by inadvertent operation, to a low-gear with the reverse gear system being put in the ON position (being put in the position shown in FIG. 7), in other words, with the motorcycle being driven backward, the conventional reverse gear system is configured so that a force is applied to the idler gear 102 to disengage the idler gear from the main-shaft-side gear 100 to release, from the ball 104, the shifter 103 provisionally held in the forward position, thereby shifting the shifter 103 to the retracted position. Accordingly, in a case where the motorcycle is driven backward at a high speed, where the motorcycle is driven backward downhill, or where the accelerator is depressed during backward driving, when a difference having a certain value or above is caused between the torque of the main shaft and the torque of the countershaft (in other words, when a strong engine brake having a certain value or above is activated), the shifter 103 has been shifted to the retracted position as in the case where inadvertent operation is done. In such a case, a motorcycle rider has been obliged to depress the shifter 103 into the forward position again.